Drawing or rolling process



.Patented Oct. 27, 1925..

UNITED; STATES PATENT j OFFICE.

JEAN GUILLAUMEIDE LATTRE AND HENRY HARDY, OF PARIS, FRANCE, ASSIGNORS,

BY DIEECT AND MESN'E ASSIGNMENTS, TO BERNARD E. POLLAK, OF NEW YORK,

The whole forms a litre of solution having DRAWING on ROLLING rnoonss.

. in; Drawing. Application filed March 2a, 1923. Serial no. 828,984.

To all whom it may concern:

Be it known that we, JEAN GUlLLAUME DE La'r'rnn and HE RY HARDY, the first a citizen of the Republic of France, and the second a subject of the Belgian Kingdom, both residing at Paris, Seine Department, No. 2 Avenue Alphand, in the Republic. of France, have invented certain new and useful Improvements in Drawing or Rolling Processes,

of which the following is a specification.

When pieces of metal are subjected to the drawing or rollin process, it is generally found necessary a ter eachpassage through the machine, to proceed with an annealing of the pieces in order to prevent any hardening of the metal, the said pieces being then cleaned by the dipping process so as to remove the oxides resulting from the anneal ing. To obviate such operations, which are expensive as well as prejudicial to the good qualities of the metal, it has been proposed to cover the pieces with a thin layer of a soft metal which acts as a lubricating substance, and in this manner the piece is enabled to traverse the machine several times without annealing. Lead or its alloys were considered useful for this purpose, but attempts made in this direction failed to give practical results, since the lead could not be made to adhere to the pieces in the proper manner, nor could the pieces be properly drawn out, for the lead showed a tendency to clog up the drawing dies, and it was also difiicult-to remove the layer from the finished pieces, this being however necessary to make them saleable. V In the present invent-ion, we obviate these 7 drawbacks by depositing upon the said pieces slayer of copper and mercury or brass and mercury, the mercury forming an amalgam. v

Qur process is for exampleas follows: The pieces are carefully cleaned by dipping and are then covered with a thin layer of amalgam by the electrolytic rocess, using a bath having as-a base salts 0 copper, zinc and mercury, preferably composed as follows ' Grams. Sulphitocyanide of copper and potassium Sulphotocyanide of zinc and potassium 25 Cyanide of mercury 3 Water about 980 sium has the formula Cu density 1.034 and resistivity 18:25.

The sulphitocyanide of cop er and otas- (8N) 6K N.K S0 and is obtained by the combination of copper cyanide C11 (CN) 6KCN with potassium sulphite K 80 Likewise,-the sulphitocyanide of zinc and potassium is obtained by the combination of zinc cyanide with potassium sulphite.

. The formula for the cyanide ofmercury is Hg( )2- The preferred conditions for electrolysis are the following:

Current tension='24 volts. Current density=2 amperes per dmfi Temperature of the bath= C.

-The above conditions are not absolutely indispensable, and can be somewhat varied Without departure from the invention.

Due to the presence of mercury, which is the softest of the metals, the layer deposited upon the pieces forms the best possible lubrication; the coefficient of friction is now entirely small, and it varies but little in relation to the pressure between the friction arts; the said layer is extremely thin, and is obtained in a rapid and inexpensive manner; it adheres very strongly even in the case of iron or steel pieces, and it can be entirely removed in a ready manner after the completion of the work, with recovery of the various metals.

Claims:

1. A process for forming a metallic lubricating coating upon articles to .be subjected to drawing, rolling, or the like, com,-

prising, electrolytically depositing upon the articles a la er of copper and'mercury form ing an ama gam.

2. A process for forming a metallic lubricating coating upon articles to be subprising, electrolytically depositing upon the articles a layer of copper and mercury forming an amalgam, the electrolytic bath used consisting of a solution of copper and potassium sulphitocya-nide, and mercury cyanide.

4. A process for forming a metallic lubricating coating upon articles to be sub- 5 jected to drawing, rolling, or the like, comprising, electrolytically depositing upon the articles, a layer of brass and mercury formiu an amalgam, the electrolytic bath used consisting of a solution ofv copper and potassium sulphitocyanide, zinc and potassium 10 sulphitocyanide, and mercury cyanide.

In testimony that We claim the foregoing as our invention we have signed our names.

JEAN GUILLAUME DE LATTRE. HENRY HARDY. 

